1. Field of the Invention:
The invention relates in general to transportation apparatus, and more specifically to transportation apparatus which includes a moving handrail, such as moving walks and escalators.
2. Description of the Prior Art:
Transportation apparatus for transporting passengers between spaced landings, such as moving walks and escalators, include a continuous, flexible handrail on each side of the conveyor portion of the apparatus. Each handrail is driven about a closed loop by one or more handrail drive units, which are operated by, and thus in synchronism with, the conveyor drive unit, or units. The closed handrail loop includes an upper run to be grasped by conveyor passengers, and a lower or return run, and curved end portions which connect the upper and lower runs.
In the modular type of construction set forth in U.S. Pat. No. 3,707,220, which is assigned to the same assignee as the present application, in which one or more drive units are mounted in the support truss of the transportation apparatus, each conveyor drive unit may drive a handrail drive unit via a drive chain or belt. A conveyor drive unit is positionally adjusted and fixed for proper engagement with the conveyor, and then the handrail drive unit is positionally adjusted and fixed for proper tension in the drive chain or belt. Subsequent readjustment of the position of the conveyor drive unit, requires readjustment of the handrail drive unit. Wear and/or stretch of the drive chain or drive belt requires readjustment of the handrail drive unit.